Heat transfer unit



May 3, 9 3- c. w. WIEGAND HEAT TRANSFER UNIT Filed May 1951 2 Sheets-Sheet l May 23, 1 3- c. w. WIEGAND HEAT TRANSFER UNIT Filed May 6, 1931 2 Sheets-Sheet Patented May 23, 1933 UNITED STATES PATENT OFFICE HEAT TRANSFER UNIT Application filed May 6, 1931. Serial No. 535,521.

This invention relates to new and useful improvements in heat transfer units and more particularly to heat transfer units of the circulating air and extended heating surface type.

The primary object of the invention is to provide a heat transfer unit of the stated character having a relatively high efliciency and economical in operation.

Another object of the invention is to provide a heat transfer unit of the stated char acter constructed to pass the air through the said heat transfer unit at relatively high velocities.

Another object of the invention is to provide a heat transfer unit of the stated char acter having a direct, unbafiled passage for the air through the heat zone.

The invention further resides in features and details of construction herein set forth and shown in the accompanying drawings, in which:

Figure 1 is a View in perspective of the heat transfer unit constituting the invention:

Fig. 2 is an enlarged sectional plan view of the heat transfer unit; a

Fig. 3 is a sectional View on line 3-3, ig-

Fig. 4 is a transverse sectional view on line 4-4 Fig. 2; and

Fig. 5 is a detached sectional view showing a modification in the construction of the 35 steam tubes.

Heretofore, heat transfer units of the air draft type have for the most part been constructed on the indirect air flow principle, thus creating a tendency to retard the ve- 4o locity of the air passing through said heat transfer unit. Furthermore, inair draft heat transfer units in the past, the extended air fin surfaces have been heated by transverse contact with the heating eleinents, and difiiculty has been encountered in the inability of such a system to adequately heat the air fins throughout the entire surface thereof. Such obstacles as the above have become factors of great economic importance in the attempt to efficiently operate he t transfer units constructed on the above principle.

j By this invention I provide an air draft heat transfer unit having an uninterrupted, direct flow of air therethrough. The principle of direct flow through tubular air fins, vertically disposed as in the present instance, effects an air flow through the heat transfer unit at comparatively high velocities which may be increased by decreasing the diametrical size of the tubular fins. The air passing through the tubular fins produces an effective turbulence of the air which increases the velocity, and subjects every particle thereof into contact with the surface of the air fins'at some time during the passage of the air through the fins. This produces a more efficient method of heating the air. By use of the cylindrical tubular fins, as in the'present instance, and fused 10 line contact of the air tin with the heating element, the said fins are capable of being heated to an even temperature throughout the length, and entire circumferential surface thereof, the heat waves traveling laterally about. the tubular surface at each side of the line of contact with the heating'ele ments and overlapping at the'most removed point on the said surface from the heating element. The effect of the'high velocity of the air through the device together with the turbulent action of the air in the fins, results in a small decrease in the temperature difference of the intake and exit air than has heretofore been available with steam of sub- 8 stantiall-y the same heat content. However,

it is Well known that the efficiency of the performance of heat transfer units is meas ured by the condensation factor and, by my invention, While the temperature difference between the intake and exhaust air is somewhat smaller than heretofore encountered in similar units, the condensation factor of a unit embodying my invention is more than doubled, resulting in an effic iency of operation upwards of 200 percent. The decrease in the temperature difference in the intake and exhaust air passing through the transfer unit ismore than offset by the relatively greater increase in velocity of the air emerging from the said unit and which effects a complete circulation of the air in the space into which it is exhausted.

Referring to the drawings, the heat transfer unit constituting the invention comprises in general a casing or cabinet 1 having intake and exit ports 2 and 3 respectively. The said ports in the present instance are suitably protected against entrance of foreign particles into the cabinet by gratings 4:. A pair of steam headers or reservoirs 5 are secured within the cabinet 1, a suitable distance above the base and adjacent the sides thereof as shown in Fig. 2 of the drawings. In the present instance passage between the headers 5 is accomplished through elongated oval pipes 6 connected therebetween, the longitudinal cross section axis of the said tubes 6' being disposed vertically with respect to the base of the casing l of the radiator. In the present instance a pair of pipes 7 are connected at one end to each of the steam headers 5, the other end of the said pipes passing externally of the casing 1 at the back thereof. It will be seen that by connecting the external ends of the pipes 7 to a suitable steam line, steam may be passed in one of the said pipes 7 to the adj acent steam header 5, and through the steam tube 6 to the second steam header 5, from which the steam passes through the other pipe 7 externally of the cabinet 1 to the steam line.

A plurality of cylindrical tubular air fins 8 are disposed vertically within the cabinet 1, as shown in Figs. 2 and 3 of the drawings, in such a manner that the circumferential. surface of each one of the said tubular fins 8 has a line contact with one of the heating tubes 6, extending the greater portion of the length of the said fins 8, and'with at least one other air fin. The contact between the tubular air fins 8 and the prime heating surface 6 is accomplished by means of a fused metallic bond between the said tubes 8 and the the prime surface.

A modification of the construction of the steam tubes is shown in Fig. 5, wherein the said steam tubes passing between the steam headers 5 are cylindrical in shape, designated as 9, and in which case it is desirable to provide a plurality of such tubes disposed one above the other, to effectively heat the surface of the air fins 8, as shown in Fig. 5 of the drawings.

A heat transfer unit of this type, and involving the principle discussed at the beginning of the specification, may be utilized forpurposes wherein it is desired to cool circulating water, as for example, the circulating water in water-cooled internal combustion engines. The water to be cooled may be passed, in place of steam or water ordinarily used for heating purposes, through the pipe 7, the reservoirs 5 and their connecting tubes 6. The passage of cold air inwardly of the port 2 through the cylindrical tubular air fins 8 and out of the exit port 3 of the heat transfer unit effects a comparatively greater temperature drop in the circulating cooling water than has been accomplished in cooling circulating water for internal combustion engines by air heretofore.

It will be apparent from the foregoing description that the. principal .described in the preferred embodiment of'my invention 'forthe purpose of description, may be embodied many systems involving heat transfer, where the cooling of liquids or the condensing of gaseous mediums, or even cylinder walls in air cooled engines may be desirable.

The transfer of heat in the above instance is from the prime surface to the tubular fins, the heat being absorbed by the passing of air through said fins. This action may be reversed as in refrigeration wherethe heat in the air is transferred to the said fins, the said fins conducting it to the prime surface in which a heatabsorbing medium is used, thereby cooling the air passing through the fins.

While I have stipulated in the foregoing description that the tubular air fins be circular in cross section and form, it will be apparent that tubes having square, rectangular, elliptical or variations thereof for the crosssectional shape thereof, may be iningrfrom the spirit thereof.

I claim:

corporated in my invention without depart- 1. In a heat transfer unit of the stated character, steam headers connected in ,a circulating line,tubes connecting said headers and affording aprime heating surface, cylindrical tubular airfins contacting at least in part with the tubes and adjacent air fins through which air is adapted to pass to be heated, the said air fins being positioned to .s

effect a direct passage of the air through the heat transfer unit.

2. A heat transfer unit of the-type described comprising a prime heating surface,

and a plurality of contiguous cylindrical tubes, each in bonded contact with said surface and adjacent tubes, the said tubes effecting a direct turbulent flow of air, through the heat transfer unit.

3. A heat transfer unit of the type described, comprising a cabinet having an intake portfor cold air adjacent the bottom and an exhaust port forv warm air adjacent the top. thereof, a pair of. headers secured to the sides andinternally of the cabinet, tubes separating and affording passage between said steam headers and affording a prime heating surface, an inlet pipe connected to one of said headers, a second pipe connected to the other of said headers for passage externally of the unit, and a plurality of tubular air fins each contacting the greater part of the length thereof with one of the tubes, the said air fins being vertically disposed Within the cabinet to effect direct passage of the air through the heat transfer unit.

4. A heat transfer unit of the type described comprising a cabinet having an in- 10 take port for cold air and an exhaust port for Warm air, tubes in said cabinet affording a prime heating surface, and a plurality of upright contiguous tubes, each in contact with the said heating surface and the adja- 15 cent air fins.

5. A heat transfer unit of the stated character comprising a cabinet, tubes in said cabinet affording a prime heating surface, and a plurality of vertical contiguous cylindrical 20 air fins, each in contact with said surface and adjacent fins, the said tubes effecting a direct turbulent flow of air through said unit.

6. In a heat transfer unit of the stated character comprising a cabinet, having an intake port for cool air adjacent the bottom and an exhaust port for Warm air adjacent the top thereof, and a plurality of vertical contiguous cylindrical tubes in said cabinet of) affording a direct turbulent flow of air throu 'h said cabinet.

cfiARLEs WILLIAM WIEGAND. 

